The present invention relates to an insect repellent. Chemical compounds which are intended to keep insects away or to drive them away have been known for a long time. These insect repellents are described in detail, for example, in the technical book entitled "Die Insektizide" (Insecticides) by Werner Perkov, pages 533-540. Among others, the following compounds are described in particular detail: phthalic acid dimethylester, 2-ethyl-hexane-1,3-diol, butopyronoxyl, dimethylcarbate, 2,3,4,5-bis-(butylene)-tetrahydrofurfurol, pyridin-2,5-dicarbonic acid-di-n-propylester, and m-toluol acid-N,N-diethylamide (diethyltoluamide). The known repellents are intended for personal use, that is to say, they must be applied upon a person's skin and thus prevent the person treated in this fashion from being stung by, for example, gnats.
Further details as to the way in which the repellent effect takes place are not known. The deterrent effect has nothing to do with an odor or taste which can be defined as being pleasant or unpleasant or otherwise as far as human sensation is concerned. It is further quite difficult to predict from the chemical identify of a composition whether such will be effective as an insect repellent.
It is known that certain insecticides also act as repellents. For example, pyrethrum spirals are set on fire and glow slowly. The developing pyrethrum vapors have a repellent effect on insects.
The German patent application laid open for inspection No. 2,534,765 also describes the repellent effect of citral, an aldehyde, which is found in volatile oils of lemons, lemon grass, and oranges.
The American market furthermore offers a product developed especially for garbage cans which is based on dichlordimethylvinylphosphate (DDVP). This product however is intended to kill insects in the garbage can; this product does not create a repellent effect.
The known repellents have only a very low vapor pressure, and therefore; do not appear to be very suitable for use as repellents in an independent vaporization mechanism. They have an effect only if they are applied to the skin because they drive insects away when these insects approach the human body. In general, it has been observed that the insects very briefly sit down on the treated skin, but then fly off again right away without, for example, stinging.
Insecticidal products based on DDVP referred to hereinabove suffer from the disadvantage that DDVP is a strongly toxic substance. Because it is not desirable to have such poisonous substances in the kitchen and, on the other hand, because application during use naturally is such that the product can readily be reached by infants, these facts represent an extremely serious disadvantage. The previously mentioned pyrethrum spirals are impractical to handle and cannot be considered for use in trash cans.
The problem therefore is to develop an insect repellent, especially for trash cans and the like, which does not possess the above-described disadvantages and which in particular will meet the following requirements:
1. Maximum effect wherein the insects are extensively kept away from the trash can. This is to prevent breeding grounds from developing in the trash cans and having disease germs spread by the insects.
2. The bad odors developing in the trash can should be extensively neutralized or covered over.
3. The repellent must practically be nontoxic because, when used in any kitchen, no toxicologically objectionable vapors must reach foods and, on the other hand, children must not be able readily to get at the product when, for example, it is used in the trash can lid.
4. The effect of such a dispenser should last as long as possible.
Numerous series of experiments conducted over a long period of time revealed that this task can be accomplished by the composition of the present invention.